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I'm debating how wire will be run in my workshop. I asked a similar question earlier, but this deals specifically with working with conduit.

First off, I think I prefer running raceway along the walls. However, I'm considering metallic conduit as a alternative. If I run conduit, how would I go about adding another outlet (or something) in the middle of the conduit run? Do I have to disconnect everything downstream from where I want the addition, pull the wire out of the conduit then cut the conduit, add the new receptacle and pull the wire back down the conduit to the downstream receptacles? This seems like an overly laborious effort just to add "something" else to the current conduit, but I see no way of cutting the conduit without pulling the wires.

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  • Generally you can use the old wire for longest half so the only waste is the shortest side from the box. Generally it isn't practical pull the wire 12" one direction and cut the wire while still in the j-box because it is difficult to ream the conduit with wire in the way. – NoSparksPlease Oct 24 '20 at 14:59
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Surface raceways will save you a lot of work in many situations, especially big raceway where you mount receptacles in the cover. You can add wires from the nearest receptacle on the same circuit to the new receptacle. These surface raceway products are expensive, some are very expensive, but it's not too hard to work with and you can get a great finished installation without any special tools. With conduit, you really need to buy a bender and learn how to use it to get a nice finished install.

Of course with conduit, you could just backtrack. Put the new box under the existing conduit, run a new conduit and wires from the nearest box to the new box. It doesn't look as nice but it's totally fine.

If you really don't like the idea of boxes at different heights when you backtrack - you could enter the tops of the boxes on the left and exit on the right with pull elbows...

pull elbow

... or, you could run the conduit down at baseboard level and stub 90s up into the box left and right. That might look a little nicer. You get the idea, you can get creative.

EIther way, then you'll have clear space between for new boxes. This will be easier to modify if you add boxes. You can use a side knockout to backtrack and hit a box set at the same level.

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    Another person asked a similar question a few weeks ago on how to best wire a shop. The answers others (and me) gave should be of help. Hopefully I got the link right: diy.stackexchange.com/questions/205049/… – George Anderson Oct 24 '20 at 12:53
  • @GeorgeAnderson - nice pictures in your post, looks like a deluxe setup – batsplatsterson Oct 24 '20 at 13:13
  • @GeorgeAnderson Hey, that was me! I even had that linked in my question. Anyway, in the old question I was considering neither conduit nor raceway. Now I'm thinking I need one or the other (safety first) and I'd love to do raceway, but it's so darn expensive. Conduit isn't as flexible, but that's probably where I'll have to go. – tnknepp Oct 24 '20 at 20:42
  • Too funny. I should have clicked on the link first! Yeah, it gets expensive, but it's so flexible for future proofing your install. When deciding, don't just consider the total cost of either solution, instead, consider the difference in cost so you can determine if the additional cost is worth it to you. I'm surprised others here didn't mention BX cable or flex conduit. I don't like them, bc you just can't make them "look nice", but might be an inexpensive, if not aesthetic alternative. I also really like Harp's suggestion. But IMHO, go for the gold and do a raceway. – George Anderson Oct 24 '20 at 22:34
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Yes, that's basically how it's done but there is a bit more to it. You have to replace the "downstream" wire anyway because it will not be long enough to make the connections to the new outlet and still reach the far end.

This is why it's important to plan for where you need outlets BEFORE installing so that you avoid this situation altogether.

BTW - you usually have the same problem even without conduit as there is generally not enough slack in any wire run to add in outlets.

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  • Well that's a bummer, but good to know there's not trick to it. – tnknepp Oct 24 '20 at 12:24
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Don't make it harder than it is :)

Nothing easier

At the last junction box before your planned box (or the first one past it, or wherever, really)... knock out one of the knockouts that faces your planned box. (Or is 90 degrees to it).

Extend some new conduit out of that knockout (using an LB, LL, LR or pulling elbow to round a 90 corner if need be). Mount the new box so this new conduit goes straight into it.

Install your receps in the new box. Run new wires down the new conduit "back" to the box you tapped off of, and either splice in there, or continue through that box to wherever you're going.

If you need more cubic inches, use a taller domed cover or mud ring or extension box.

If you would exceed 4 circuits per pipe or run out of conduit fill, lay a second pipe parallel to the original on the route needed.

However you can avoid this in the first place by...

Simply installing the junction boxes you might need before pulling any wire. You're not obliged to put receptacles or switches in every box you install. You can just put a 25 cent cover plate on the box, and leave it there for future expansion.

Cost of adding an empty box to a conduit run is under $2 if you shop smart.

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You have spelled out exactly what you need to do. There is no way to add the junction box without removing the wire and then cutting the conduit. The main issue is protecting the wire from any damage. You will probably have to replace one end of the wire because because there won't be enough slack to extend the wires 6" from the new box to connect up the new outlet.

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  • Thanks Jack. The 6" you refer to is the code standard, correct? – tnknepp Oct 24 '20 at 12:23
  • Yes, NEC 300.14 says you must have 6" in the box where it emerges from the cable or raceway. – NoSparksPlease Oct 24 '20 at 14:50

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